A consequence of the downwelling is that the principal interior gyre is prevented from reaching the east coast and a secondary gyre is formed in this region.
Flow over the shelf below the surface layer consists of two anticyclonic gyres connected by a central cyclonic flow.
As the sun heats it, the water in the gyre evaporates- but then blows away.
Cyanobacteria remain critical to marine ecosystems as primary producers in oceanic gyres, as agents of biological nitrogen fixation, and, in modified form, as the plastids of marine algae.
Flotsam can be blown by the wind, or follow the flow of ocean currents, often ending up in the middle of oceanic gyres where currents are weakest.
While waters of differing salinity and temperatures could become stratified, models predict that the seaway was well-mixed due to the circulation gyre.
Thereafter, deep convection gradually developed around a large cyclonic gyre which accompanied the wave.
Operculum is type c, with a gyre that bears a raised spiral row of strong, distally-tapering spines (hence the specific epithet, echinogyra).